There are essentially two methods for the so-called electronic control of machines. In both methods, electrical control signals are fed to the mchine and these signals are received through optical, magnetic, electronic, or mechanical scanning of the program carrier.
In one method, which can be used particularly in connection with machines for making picture patterns, such as, for example, knitting machines, weaving machines, printing machines, machines for making mosaic pictures and the like, the program carrier consists of a two-color or multi-colored drawing which can also be present herein the form of a grid or raster pattern or which consists of the image of this drawing on the screen of a television tube which is a part of an optical-electrical picture storage unit. The design to be produced by the machine is in these cases stored in the program carrier in an analog, visually recognizable form.
In the other known method, which is suitable for the electrical control of machines of all kinds, the program carrier consists of a control strip having optically-magnetically, or mechanically scannable markings, on which the control signals, to be fed into the machine, are stored in a visually nonrecognizable order and in digital form. The same applies to the case where the storage or memory unit of the data processing installation is used as program carrier.
The methods mentioned are preferably suited for the electronic control of complicated functional procedures and have accordingly comprehensive program carriers. On the other hand, they are much too expensive for the control of relatively simple functional procedures, for example, in textile machine technology, especially in circular knitting machine technology. It is therefore still customary today to use, in addition to electronic control devices the convention mechanical design devices, such as design wheels, trip cams, switching chain apparatuses, and the like, when small design guides are to be made. However this has the disadvantage that either two different machines are needed or that the electronically controllable machines must additionally be equipped with means for mechanical control.
As illustrated in U.S. Pat. No. 3,680,331, it is frequently desirable in machines controlled by control strips, in order to avoid excessively long and therefore expensive control strips, from time to time to interrupt the control commanded by this strip and instead to switch to a simpler type of control. The reason for this is that the knitware to be made alternately can have complicated connection and/or color designs and areas of simple knitting, so that small, complicated guides alternate with large-area, simple guides, whereby the production of a separate program carrier is not worthwhile for simple guides.
It is understood that by "guide" or "period" what is meant is the regular, periodic recurrence of the various equivalent points of the material to be produced, for example, knitware, or that part of the special functional procedure of the machine which is constantly repeated. Simple guides can extend over a few stitches in a stitch course in the case of knitware. For example, if it is desired to make two white and two red stitches alternating in steady repetition, then it is necessary within one period of four stitches or four work cycles of the machine to supply two control signals to the system that handles the white color and to the system that handles the red color. If the guide on the other hand is to consist for example of two red stitches between three white stitches, then within a period of eight stitches or eight work cycles of the machine, it is necessary to feed six control signals to the white system and two control system in a certain order. Until now, this has been accomplished through the corresponding programming of the program carrier or by means of mechanical expedients, whereby a separate control track of the control strip or a corresponding mechanical control device is assigned to each work station of the machine.
It is an object of this invention to avoid the prior art disadvantages and creating a method and device by means of which it will be possible to feed into an electronically controllable machine the electrical control signals necessary for the control of simple processes without the use of a specially made program carrier.